136 MAXIMUM SPECIFIC ELECTRICAL CONDUCTIVITY IN CHEMISTRY. 
maximal. Professor Brown states further * that ‘it was found that sulphuric acid could 
not penetrate into the grain, not only from volume normal solutions, but also from 
solutions containing 9, 18, or even 36 grammes of acid per 100 ¢.c. In the case of the 
seeds immersed in the strongest acid, however, the interior remained dry, presumably 
because the power of the seed contents of imbibing water was insufhicient to overcome 
the osmotic pressure of the liquid.” 
“The vitality of the embryos was not destroyed by steeping the seeds in the acid 
solutions; when placed under suitable conditions they all germinated.” 
Now, 86 grams of sulphuric acid per 100 ¢.c. corresponds to a percentage of 29°7 
H,SO,, which is only 0°3 per cent. below that corresponding to maximum conductivity. 
It is suggested that in plant metabolism the tendency towards increased specific 
conductivity is a directing factor, both in the case of foliage leaves and of seeds. 
Increased specific conductivity results from the progress of the reactions in the one 
direction or in the other, according as the sap has the character of an ultramaximal, 
or of a premaximal solution. It is important in this connection to note that increase 
in specific conductivity does not solely result from the actual addition or removal of 
water from the sap solutions, but that it also results from polymerisations or con- 
densations especially of the aldol type in submaximal, sub-premaximal, and sub- 
ultramaximal solutions. t 
It is hoped in a subsequent paper to develop the application of the hypothesis to 
chemical systems generally, and especially to those occurring in plant and animal 
metabolism. 
Several conjoint papers have been, or will shortly be, published bearing on different 
points related to the inquiry which is summarised in this paper. 
I take this opportunity of thanking those who in one way or another have given 
me kind assistance. My thanks are very specially due to Mr Anprew Kune, F.C.S., 
for long-continued and invaluable analytical assistance. I also gratefully acknowledge 
the receipt of a Research Grant from the Carnegie Trust. 
* Proc. Roy. Soc., 1909, vol. 1xxxi. p. 82. 
+ See page 124 et seq. 
Herior-Watr CoLiece, 
[pINBURGH. 
